Q2.Find the scalar and vector components of the vector with initial point (2, 1) and terminal point (– 5, 7).
Answer : Option CExplaination / Solution: The scalar and vector components of the vector with initial point (2, 1) and terminal point (– 5, 7) is given by : (- 5 – 2 ) i.e. – 7 and (7 – 1 ) i.e. 6. Therefore, the scalar components are – 7 and 6 .,and vector components are -
Q5.Write down a unit vector in XY-plane, making an angle of 30° with the positive direction of x-axis.
Answer : Option DExplaination / Solution: Let r→=xiˆ+yjˆbe a unit vector in XY plane,making angle 300 with positive X axis,so we have the vector as r→=cos300i^+sin300j^ x=3√2;y=12,(∵∣∣r→∣∣=1). ∴r→=3√2iˆ+12jˆ is the required vector.
Q7.Find the position vector of a point R which divides the line joining two points P and Q whose position vectors are externally in the ratio 1 : 2. Also, show that P is the mid point of the line segment RQ.
Q9.The scalar product of the vector i^+j^+k^ with a unit vector along the sum of vectors 2i^+4j^−5k^andλi^+2j^+3k^ is equal to one. Find the value ofλ.
Answer : Option AExplaination / Solution: Let a→=iˆ+jˆ+kˆ,b→=2iˆ+4jˆ−5kˆ and c→=λiˆ+2jˆ+3kˆ,
Therefore, a unit vector along b→+c→ is given by:
Also, scalar product of i^+j^+k^ with above unit vector is 1.
Q10.The scalar product of two nonzero vectors a⃗ and b⃗ is denoted by
Answer : Option AExplaination / Solution: The scalar product of two nonzero vectors a⃗ and b⃗ is denoted by a→.b→.and is defined bya→.b→ =∣∣a→∣∣∣∣∣b→∣∣∣cosθ
Total Question/Mark :
Scored Mark :
Mark for Correct Answer : 1
Mark for Wrong Answer : -0.5
Mark for Left Answer : 0